Luas Cross City (LCC) was completed on time and on budget by Sisk Steconfer JV

Luas Cross City launch, December 2017

Significant urban improvement

LCC is recognised as being one of the most challenging and complex projects undertaken by the Irish State in the modern era. The successful delivery of the project was seen as being nationally important in terms of Ireland’s reputation and ability to attract future investment, both in national infrastructure and the economy in general.

The standard of finished product has been recognised by the client, operator and stakeholders as being exemplary. The rebuilding and rejuvenation of the city centre streets which incorporate the extension has also left a positive legacy for Dublin city.

O'Connell Street, Dublin city centre

Dublin city centre works

As completed, LCC comprises a 6km extension northwards from the previous Green Line terminus at St. Stephen’s Green, passing through Dublin city centre to the north‐west inner city suburbs, and terminating at an interchange station on the suburban railway line at Cabra’s Broombridge station.

The city centre section is comprised of a single-track loop arrangement, enabling different service patterns to be employed according to demand. The new line crosses the existing Red Line at O’Connell Street and Marlborough Street, with engineering connections and passenger interchange at both locations.

O'Connell Bridge, Dublin city centre

Interface management

The overall Luas Cross City project consisted of a number of different contracts which were carried out in advance or parallel with the main infrastructure works (BXD-400). We managed the relevant interfaces and delivered all of the civil infrastructure requirements in the design and construction of the project, including control systems, heritage works and utilities.

We also successfully achieved the timely handover of over 200 interface milestones relating to designs, construction, installation and testing/commissioning handovers; these could not have happened as seamlessly as they did without successful collaboration throughout.

This scheme was the first light rail project in Ireland that was delivered to the newly introduced Authorisation for Placing in Service (APiS) requirements of the Commission for Railway Regulation (CRR). Covering both quality and service aspects, this independent review imposed external checks and requirements to ensure that the delivered product was acceptable for use by the travelling public.

Utilities

As was always bound to happen when working in a city as old as Dublin, we encountered a vast amount of buried and uncharted services at frequent stages throughout the project. In each case, these discoveries required unique redesigns to be developed at short notice before being agreed with the respective utility owners. Some of the discoveries also involved the use of special tools and equipment to protect both the services themselves and our construction operatives who were working on them.

Sisk Steconfer JV team at Westmoreland Street

We are capable of offering our clients a bespoke service on every project

Red line tie in (Marlborough Street/Abbey Street)

13,600m3

On street, concrete track bed and shoulders poured

3,398

Number of people who worked on the mains infrastructure project

1,520

Tonnes total weight of the tracks

Red line tie in (Abbey Street/O'Connell Street)

Traffic/stakeholder management

The traffic management requirements involved in the project were extensive to say the least, particularly in relation to the on-street section. As planned, they were set to involve the most unprecedented levels of ongoing city centre traffic management in decades, if not centuries, which made it all the more imperative that one of our core project mantras was to “keep Dublin moving."

Regardless of the unavoidable levels of disruption which were going to occur throughout the project, vehicle traffic and pedestrians would still have to move freely through the city at all time, allowing business and general city life to function as normally as possible in the process.

As such, SSJV remains indebted to our traffic management colleagues in Dublin City Council (DCC), Dublin Bus and Ireland’s national police service, An Garda Síochána. Working together along with Dublin business bodies and owners, we were able to develop and facilitate traffic planning which balanced our construction needs with those of the general populace.

Part of these plans meant that a large amount of “out of hours” working and delivery schedules were organised in order to achieve maximum work crew outputs at all times, without causing undue nightwork disruptions to city centre residents.

An excellent Transport Infrastructure Ireland (TII) / National Transport Authority (NTA) website, 24-hour telephone hotlines and contractor emails allowed for dissemination of information and real-time engagement, and we also facilitated “Town Hall” meetings in local hotels, presenting our broad proposals to business leaders and interest groups. These initiatives made the whole process more manageable, and gave stakeholders a forum to solve issues and diffuse any tensions.

Over half of the project was constructed in a live city environment and this was completed without requiring any business premises to close, while also maintaining traffic and pedestrian corridors throughout. This was achieved through considered planning and extensive engagement with local authorities, local businesses, and transport providers.

Last tracks being laid at Broadstone

Community enhancement

LCC provides a fast, reliable and modern transport system for communities to be proud of. It efficiently links the various city precincts and provides connectivity between expanded areas of suburbs and larger areas of the city centre, transforming local neighbourhoods in the process through rejuvenations such as extensive tree planting along the rail corridor and improved access to Cabra’s Mount Bernard Park.

LCC’s increased availability and connectivity means that public transport is now a more viable, cost-effective and time-saving option than before for many who work or live along the extended route.

Local CSR initiatives which SSJV carried out included installation of a new community playground at Broadstone and refurbishment of a local community centre at Broombridge.

Broadstone new playground opening day

Conservation

The upgrading of two existing bridge structures along the proposed LCC extension was a detailed process, involving the reinforcement of the existing parapets using proprietary anchor systems compatible with the preservation of existing masonry; provision of high containment on the wing walls of both bridges.

One of the structures (which had previously been used by the Midland Great Western Railway) also required extensive heritage repair works, as well as structural assessment to meet with conservation requirements.

Considering that LCC runs along some of the most historically important streets of Ireland’s capital city, archaeological considerations were also a huge factor throughout the project. Our deep excavations in many areas unearthed a plethora of fascinating archaeological structures and remains, including long-defunct canal docks such as Broadstone Harbour, Victorian-era railway terminals, and a mass graveyard at Grangegorman, where almost 1,700 victims of Ireland’s 1832 cholera epidemic had been buried.

Phibsborough stop

Of all the 13 new stops, the one at Phibsborough presented a huge challenge on the project. The existing heritage structures, remote site access and demands of modern-day civil engineering design regulations all contributed to make Phibsborough a mini-project in its own right.

In particular, the process involved the retention of a number of old structures at the site. These all fell under conservation criteria required by the Irish Department of Environment, Heritage and Local Government.

Liam Whelan Bridge replacement

"The Luas Cross City project has been one of the most challenging we have ever been involved in and its completion on time is a testimony to the quality and commitment of the people who worked on it from Sisk."